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The Wharton olefin synthesis or the Wharton reaction is a chemical reaction that involves the reduction of α,β-epoxy ketones using hydrazine to give allylic alcohols. [ 1 ] [ 2 ] [ 3 ] This reaction, introduced in 1961 by P. S. Wharton, is an extension of the Wolff–Kishner reduction .
The Wolff–Kishner reduction is a reaction used in organic chemistry to convert carbonyl functionalities into methylene groups. [1] [2] In the context of complex molecule synthesis, it is most frequently employed to remove a carbonyl group after it has served its synthetic purpose of activating an intermediate in a preceding step.
The reaction is exothermic, and the mixture can reach the boiling point, if external cooling is not applied. The resulting product, diethyl 3,5-dimethylpyrrole-2,4-dicarboxylate, has been called Knorr's Pyrrole ever since. In the Scheme above, R 2 = COOEt, and R 1 = R 3 = Me represent this original reaction.
The compound consists of a 1,2,4-triazole heterocycle with three functional groups: amine, thioamide and hydrazyl. X-ray crystallography shows that this molecule is polar but with a C=S double bond. It is prepared by the reaction of hydrazine with thiourea: [1] 2 SC(NH 2) 2 + 3 N 2 H 4 → SC 2 N 3 H(NH 2)(N 2 H 3) + 4 NH 3 + H 2 S. The ...
The Fischer indole synthesis is a chemical reaction that produces the aromatic heterocycle indole from a (substituted) phenylhydrazine and an aldehyde or ketone under acidic conditions. [1] [2] The reaction was discovered in 1883 by Emil Fischer. Today antimigraine drugs of the triptan class are often synthesized by this method. The Fischer ...
When derived from hydrazine itself, hydrazones condense with a second equivalent of a carbonyl to give azines: [11] R 2 C=N−NH 2 + R 2 C=O → R 2 C=N−N=CR 2 + H 2 O. Hydrazones are intermediates in the Wolff–Kishner reduction. Hydrazones are reactants in hydrazone iodination, the Shapiro reaction, and the Bamford–Stevens reaction to ...
Azines have been used as precursors to hydrazones: [4] [8] R 2 C=N-N=CR 2 + N 2 H 4 → 2 R 2 C=N-NH 2. They are also precursors to diazo compounds. [9] [8] [10] The coordination chemistry of azines (as ligands) has also been studied. [11] [12] [13] Acetone is used to derivatize hydrazine into acetone azine for analysis by gas chromatography.
In the first report on this reaction type the coupling partners were a tosylhydrazone, an aryl halide with catalyst system dibenzylideneacetone / XPhos. [8] As part of the catalytic cycle the diazo intermediateformed by decomposition of the tosylhydrazone forms a palladium-carbene complex with the oxidative addition complex of palladium with ...